Hinged belts are relatively new in the art for carrying bulk materials such as mineral ore and are available commerically from one known supplier, namely, The Goodyear Tire and Rubber Company. Such belts consist of a disc-shaped trough portion and a pair of flaps for covering and enclosing the material in said trough portion. Typically, hinged belts are used to move materials between various elevations. Such belts are suited for this purpose because the flaps in the closed position serve to contain the bulk material and prevent it from flowing inside the belt. Such flowing may otherwise occur due to gravity or inertia when the belt starts or stops. The use of hinged belts enables bulk materials to be transported at inclines or declines in excess of 45.degree. and at speeds up to 1000 feet per minute.
Hinged belts are continuous and extend between a head pulley and a tail pulley. A driving means is used to drive the belt. The belt typically has a loaded flight on which the trough portion faces upward for carrying the material from a loading area near a tail pulley to an unloading area near a head pulley. The belt also has an unloaded flight which extends from the head pulley to the tail pulley on the return run.
The belt is loaded with material in the area near the tail pulley. In order to load material into the belt, the flaps must be open. Once the material is loaded on the belt, the flaps are held closed. As the belt approaches the area near the head pulley, the flaps are permitted to open and the material removed. The loaded belt flight is supported between the tail and head pulleys by a plurality of troughing rolls. The loaded flight rides on these rolls and is guided thereby in the proper direction. Along the loaded flight, in the area of the steepest incline or decline, a plurality of spring loaded top idler rolls are mounted. The top idler rolls press downward on the flaps of the belt and insure that the belt flaps remain closed and that the material stays in a fixed relation on the belt without flowing. Once the belt reaches the area of the head pulley and is unloaded, the belt travels over the head pulley and is directed back toward the tail pulley supported by a plurality of return idler rolls.
In existing systems, the troughing rolls, top idler rolls and return idler rolls are all fixedly mounted on a support framework. In such systems, the supporting framework must be designed in advance so as to provide means for mounting top idlers, troughing rolls, and return idlers in the proper positions. This is often difficult because the supporting framework and rolls must conform to the contour of the terrain over which the belt travels. Because the terrain is not always known, or may be subject to change during mining operations, it is frequently necessary to make adjustments in the mounting of the rolls during installation in the field.
In prior systems, the method known to applicant to be used to facilitate the adjustment of roll positions is to journal the rolls on discrete stands. The stands are then mounted to a flat frame. In order to adjust the roll positions, shims are added to or removed from underneath the stands. This process is tedious and time consuming due to the labor involved in placing shims of the proper thickness under each stand.
Further, in existing systems, there is frequently a need to position various rolls at rake angles to direct the belt to move in a desired direction at a particular location. The need for having a roll at a rake angle and the extent of such angle often cannot be determined until the belt is operational. The need to mount a roll at a rake angle often results in additional work in the field.
It is desirable due to the hinged flap construction to have the belt move along the return flight in the closed position. This also prevents excess material not removed by scrapers at the unload station from dropping off the belt and causing an unsafe and unsightly condition. In these prior systems additional side rolls are required to guide the flaps closed as it travels along the return flight. These additional side rolls and the supporting structure add to the cost of the system.
Existing belt systems are generally exposed to contact by personnel working on or near the belt which is extremely dangerous due to the speed at which the belt is moving.
Thus, there exists a need in the prior art for a support and enclosure system for a hinged belt conveyor which facilitates positioning of the rolls during installaticn of the system in the field, enables the flaps of the unloaded flight of the belt to be placed in the folded condition without excessive stressing and by the more convenient use of guide rolls, which provides a means for opening and closing the belt flaps to prevent damage to the belts, and which increases the safety of the system.
It has been discovered that a hinged belt when approaching a drive pulley in a closed position if not permitted to open properly will cause premature wear and damage to the belt due to the flaps attempting to bend at areas other than the hinge area resulting in the belt destruction within a relatively short period of time. This problem also exists upon the return flight of the closed empty belt approaching the tail pulley. Thus a need has arisen for an orienting pulley arrangement for use with the hinged belt conveyor system which prevents the belt flaps from attempting to turn or fold back under the support rolls and bending at belt areas other than the hinge areas causing the belt to self destruct.